In artillery turrets ammunition is advanced from the magazine to the barrel via a series of straight or curved guideways. Each straight guideway is bounded by two pairs of parallel guides, the guides of each pair being separated by a distance substantially equalling the width of the piece of ammunition.
The piece of ammunition is thus always guided at two points, i.e., near the cartridge flange and near the crimping.
The two guides are respectively associated with two series of overlapping seating plates fixed on shafts perpendicular to the guides and rotated in synchronism at a rate determining a constant linear rate of displacement of the piece of ammunition inside the guideway. To this end, each plate generally has several seats, four, for example, which thus give it the shape of a Maltese cross. During rotation of the plate, the piece of ammunition is therefore taken into the seat, which moves it forward and pushes it toard the next plate. The arms of the Maltese cross are obviously profiled so as to take up the ammunition and expel it without any jolting.
At the exit of the magazine, the pieces of ammunition move one after the other in a vertical direction and are introduced into a fixed guideway in which they move parallel to each other. It is advantageous to return them to the horizontal, and for this reason the fixed guideway is constituted by two straight guideways, one horizontal and the other vertical, connected by a circular guideway in which the orientation of the piece of ammunition progressively changes.
Like the straight guideway, the circular guideway is bounded by two pairs of guides assuring continuity with the upstream guideway and the downstream guideway respectively of the inner side and the outer side of the curve. The shape of the piece of ammunition is of course allowed for to ease its passage around the curve, and for this reason the inner side is normally the one for the crimping and the outer side is the one for the cartridge flange.
It, as indicated, the upstream and downstream straight guideways are provided with overlapping seating plates driven in synchronism, the same apparatuses can clearly not be used in the same way to obtain displacement inside the curved guideway, the piece of ammunition no longer moving parallel to itself but about the center of the curved guideway instead, this being generally circular.